Panasonic CU-8ME1XPK - Low Pressure Drop Due to Refrigerant Shortage or Electronic Expansion Valve Failure

PACD011001C2 Troubleshooting
Troubleshooting Urban Multi “MX1, ME1 Series” Using R-22 181
3.26 Low Pressure Drop Due to Refrigerant Shortage or Electronic Expansion
Valve Failure
Remote Controller
Display
U0
U0U0
U0
Supposed Causes
„
Refrigerant shortage or refrigerant system clogging (incorrect piping)
„
Defect of pressure sensor
„
Defect of outdoor unit PC board
Troubleshooting
(VF052)
The suction
pipe temperature minus
coil temperature is 20 ˚C
or higher.
Resistance
is normal when
measured with the
suction pipe thermistor
(R4T or R4-1T, R4-2T) and coil
thermistor (R2T or R2-1T,
R2-2T) disconnected
from the outdoor
unit PC
board.
Refrigerant shortage or refrigerant
system is clogged. Requires
check of refrigerant system.
Replace the thermistor.
Replace the outdoor unit PC
board.
YES
NO
NO
Refrigerant shortage or refrigerant
system is clogged. Requires check
of refrigerant system.
Replace outdoor unit PC board.
YES
YES
NO
Cooling
Low pressure
is 1.0 kg/cm² (0.098 MPa) or
less.
The voltage
of X21A pins (2)
and (3) on both sides of
outdoor unit PC board (A1P) is
0.8 VDC or less.
(Pressure sensor
output
voltage)
NO
NO
YES
YES
Replace pressure sensor.
Caution
Be sure to turn off power switch before connect or disconnect connector,
or parts damage may be occurred.